For a long time, skills in CRPGs followed their pen&paper counterparts, serving the function of defining a character in more detail than the broad statistics like Strength and Intelligence would do. The game that changed this, to the best of my knowledge, was Diablo II; it is possible that Blizzard only adapted systems already present in Japanese RPGs, though. In any case – in Diablo II, skills turned to (mostly) activated abilities, requiring energy and cooldown time; in that sense, they were more like spells, and they in fact were one indistinguishable group now. The idea behind this was to give the classes focused on physical combat, which previously hadn’t much room for tactics beyond “attack”, “retreat”, “use a potion”, the same depth up to now only allowed to the spellcasters. There’s a reason that the Addict is lumping “spells” and “combat” together in one rating category.

Of course, since this is a site about crafting classical CRPGs, I will focus on the first kind of skills here. There’s still a field of possibilities – and I must admit I’m somewhat disappointed if all the skills I’m given in a game turn out to be combat-related. To make a counterpoint, here’s a list of skills we might include in a medieval fantasy CRPG. Maybe it inspires you.

Combat

(for sake of completeness):

These all usually raise the chance to hit and/or the damage dealt with the appropriate weapon. You might also need a certain skill level to even equip such a weapon:

These all usually lower penalties associated with heavy armour; you might also need a certain skill level to even equip such a piece of armour:

Leather ArmourChain ArmourPlate ArmourShieldsDodge

Backstab (chance to attack from the back and/or from shadows; depending on the game engine, this might require a previous “Hide” action)Critical Hit(raises the chance to deal additional damage depending on the weapon)Two Weapons(lowers penalties associated with wielding two weapons, and/or allows to equip a second weapon in the first place)

Survival

Climbing(used in scripted events, or to pass certain spots on the map, i.e. a high cliff)First Aid(raises the chance to heal wounds, diseases or poison)Foraging(if there’s a food requirement in your game, this might reduce it or randomly add food to the inventory in the wilderness)Hiding(used in scripted events, to bypass guardians on maps, to avoid combat, or to initiate a Backstab action)Mountaineer(to pass certain spots on the map, or to find out where these hidden paths might be in the first place)Pathfinding(to pass certain spots on the map, or to find out where these hidden paths might be in the first place)Scouting(to detect hidden paths, maybe secret doors)Senses (dangers)(to avoid being ambushed; maybe to detect traps)Swimming(to pass certain spots on the map)

Roguery

Detect TrapsDisarm Traps(lowers the chance to trigger a trap when disarming, or allows such an attempt in the first place)Hide in Shadows(if this is a special rogue skill, it is almost certainly about Backstab actions)Pick Locks(raises the chance to open a locked door or chest, or allows such an attempt in the first place)Pickpocket(raises the chance to steal items from NPCs, or allows such an attempt in the first place)Set Traps(why should only the bad guys lay out traps for enemies?)

Academic

All Magic skills (this is easily a topic on its own)Alchemy(a crafting subset; raises the chance to craft a potion, its quality, or allows to create such a potion in the first place)Ancient Languages(decipher scriptures written in languages not used in the present, probably long forgotten)Artifice(identify items)Astronomy(might be useful if your game has things like Moongates)Herbalism(raises chance to find and identify herbs during wilderness journeys; might also be a Survival skill)History(gives hints when in an area with an eventful past that might be helpful with certain tasks or puzzles)Languages(allows conversation in different languages; a sophisticated engine might allow for only basic conversation topics if the character’s skill level is low, an example would be Starflight)Learning(adds to XP)Meditation(adds to XP and/or spell points)Mining(allows to extract gems, ore, minerals from a vein)Music(if there are magical tunes in your game, this suddenly becomes important)Navigation(lowers the chance to get lost on large-scale wilderness travels and/or the time spent on them)Research(raises the chance to find the desired information from a stack of old tomes)Weaponsmith(like Alchemy, just for weapons and/or armour)Zoology(identify monsters; might also be a Survival skill)

Social

Merchant(allows the party to buy at cheaper prices and sell at higher prices; maybe the shopkeeper might make them special offers only available with a certain merchant skill in the first place)Persuasion(this might be subdivided into Charm, Convince, Intimidate, which would take Charisma, Intellect, Strength into account when the character tries to persuade an NPC of something)Sense Motive(gives an advantage in communication; raises the chance to spot lies)Streetwise(this is to civilized environments what Scouting and Pathfinding are to the wilderness)

I think this should suffice to give more variety to an adventure. And a broader selection of skills also adds to the atmosphere – it gives the idea that there is a world outside the combat screen, a world that was there before the heroes entered the picture and will be there after they left. Hopefully.